Curious about the engine, :question:

Discussion in 'Motorized Bicycle General Discussion' started by mapbike, Jan 8, 2015.

  1. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    No I wont be getting one, just saying if the module is good it will eliminate 50% of the necessary parts currently needed. Its not new technology, been around 30+ years on small engines and is basically bullet proof. I think the Chinese just continued with the technology copied from the older Russian engines. I bought 3 CGs as soon as they hit the country in maybe 04- 05? They vibed badly and the ignitions failed very shortly, maybe from the vibes.
    The new engine itself is a Flying Horse, nothing to do with Grubee I assume.

    The comments on the SRat came from the Grubee spec sheet. Its the only jug I have seen listed with the 50mm spacing. Makes it unique. Another question is why is are there 38mm cranks with too short a rod? Is it a move to detune the engines for reliability?
    If you look at Daxs webpages everything is 38mm. The crank I bought about 10days ago was sold as a 40mm. Its actually a 38mm and as of yesterday has no text under the pic about it. I don't really care as Im not about hottin up CGs. So unless Dax and the other sellers have the "magic" jug they are selling 1/2breeds. Any 38mm out there with out the 114mm rod is gonna make a 1/2 breed regardless of whose crank it is, the heavy weight crank with the ZAE50 rod or Daxes current crank with the no name rod are all gonna be 1/2Bs. Doesn't matter to me as I like lower compression for the older technology used in these engines.

    Just makes it kinda hard to figure out the thinking behind these 38mm engines.
     
  2. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    You hit on the same thoughts I have had about the 38mm stroke seeming to start to take over and the 40mm stroke engines going away sorta, I was thinking it could have to do with lower compression for less wear on the bearings for possible better reliability, this may not be it at all, but I'm wondering why all the sudden the majority of the engines are going the 38mm stroke short rod direction with the low pin piston.

    I had conversation with someone else who has been selling the 40mm stroke engines for a long while, and he told me that the crank have changed and that the engines he has had in the past are all coming with the 38mm stroke cranks now also, he told me that is why dax engines have gone to 38mm stroke also, seems that is what we are gonna be getting for the most part from here on out unless someone find a reliable ebay source for the 40mm stroke engines that have a good balanced crank.

    I'd rather have a 38mm stroke engine that is balanced fairly good and has good bearings than a 40mm stroke engine that will shake your nails off above 25mph, I have some of those bad balanced engines and they don't perform good at all unless the revs are kept really low.

    It could become that the Grube GT5 with the longer rod and the 38mm stroke could be the better choice for a performance build, looks like the engines are taking a whole new direction now for some reason, the 40mm stroke engines like dax had were hands down the best I have seen and used myself, it's a shame to see them go, but for me if the newer version can be made into a power plant that will get a bike of mine ginning good in the low to mid 40mph range like I have been able to do fairly easily with the older version, that will be fine with me, I't may just take a little extra work like shaving the jug deck and such to get compression where it needs to be.

    I'm probably gonna get one of the new dax engines soon so I can see what it's all about and see how it performs in comparison to the 40mm stroke engines I have from him.
     
  3. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    I just got off the phone with Duane at thatsdax.com we chatted for over an hour, very good conversation, he is a super good fella.

    We talked about many things in that time, but i just wanted to say here that one of my main focuses was on the engines he currently has, the 38mm stroke engines.

    He told me that they still have the Full Circle cranks and that the counter weights are a tad wider than they were on the 40mm stroke GenIV engines of the past, he said that the balance is every bit as good and that the one he has on a personal bike runs excellent with just minor mods like a banana pipe, RT Carb the RT (Puch) Head and he said he runs the RT Head on his engine without a head gasket and has about 120lbs or so compression and with a 36T rear sprocket he broke over the 40 mph mark.

    I ordered two of the lowers from him today to build one up myself so I can say first hand what I think of them compared to the 40mm stroke GenIV version he sold in the past.

    basically he told me that he has some people who prefer the 38mm stroke engines due to the fact that they seem to spool up into the higher rpms quicker and yet some like the 40mm stroke engine for the slight bit of extra low rpm grunt, but he did say that both are equally balanced fairly good and that he is very pleased with the 38mm stroke version he's currently running.

    Just thought I would pass this info along on here and give a shout out to thatsdax for taking the time to talk with his customers like he does and for doing his best to give us a good product and great customer service which has a lot of value in my opinion.

    map
     
  4. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    Great to hear! Do a thread on the engine when you get it.
     
  5. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    I will do sir.

    If I'm not mistaken, YesImLDS got one of these engines for his current build in the process and the rod in it is marked ZAF80 which identifies the engine as a GT5 geometry, I could be remembering this all wrong since I have looked at so many different things lately, but if it needs the low pin piston we will know for sure what it is... "Half Breed" because we will know it is the GT5 type crank with the PK80 type rod.

    I will see when I get them, I didn't ask Duane about which piston they use, but i think YILDS listed that detail here, possibly in this thread, I'll have to go back and check.

    I plan to set this engine up with to have optimal compression which will most likely require that the jug be shaved down since Duane said he is running his with the Puch "RT" head bolted directly to the jug without using a gasket at all.
     
  6. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    That RT head he is selling a Puch huh. I saw the same head on ebay under moped parts but didn't remember what it was advertised to fit.

    Really nice to know theres an engine source where some one knows what they have. I will be buying from him.
     
  7. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    I know it seems a bit unfair in some peoples minds to give shout outs to particular vendors on here and not mention others, but i like to give credit where it's due and among a couple other vendors here thatsdax has always been a top notch place to get many things for our bike builds so I poi t people in the direction of proven winners, especially the vendors who offer outstanding customer service and always go the extra mile if need be to resolve problems.

    Buying from a vendor who personally test his own stuff before making claims and selling it is a rare thing when we look at how most of the ebay vendors do things, thatsdax is also a business and a business needs to make a profit to stay in business, but Duane does his bezt to run it as ethical as possible and makes himself available by phone to his customers.

    I know he isnt the only one who does this but in my experience its very rare and many who give numbers to be reached can never be reached...... Thay rarely return a message here on the forum they advertise on, but they're sure happy to take your money via pay pal or whatever other means you can get it to them....lol!

    Yes the Puch 70cc Hi Hi Heads do a good job, the holes have to be drilled from 6mm to 8mm but Duane sells his either way so if someone wants one ready to go tthey an just order it from him pre drilled for the 8mm studs and slap it on and add an instant performance increase in my experience with them, they give better cooling than stock heads, better compression, and a better squish when set up right which can also add a performance boost.

    Thses heads are a great bang for the buck in my opinion, so far the fastest bike I have built was using one of these heads and it helped me to get over the 50 mph mark I had been shooting for, so I have to say I like them and the price is good on them also.
     
  8. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    A bit of insight. Today I helped a neighbor install a CG kit on his bike. He got it off ebay. He was totally ignorant of these things so he just bought one. I looked it over closely and it turned out to be a GT5. Was actually a pretty nice kit with the exception of a junk chain.

    Point is this was the smoothest, best running out of the box kit I have seen of the few(6) I have had hands on. Maybe he got lucky. I hope not because my box o engine is a GT5.
     
  9. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    it's nice that we're seeing much better balanced engines lately, Im sure hoping the lowers I ordered will be good smooth runners, Im ready to retire the old rough vibing BGF engines I have on a couple of my bikes, Im ready to have that Huffy bike riding smoothly in the upper 30mph to low 40 mph range and the old BGF will only push it comfortably to 32-34mph and then the vibes get wild even with a 36T on the 26" wheel.
     
    #129 mapbike, Feb 7, 2015
    Last edited: Feb 7, 2015
  10. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    So spent the evening looking on ebay at CG engines. Prices are down and from what I am seeing(at least externally) the majority of engines seem to be GT5s. That's seems to be a good thing. We must be in the transition of engines or something. Looks like maybe the design was to a 38mm engine and the interim engines may have been assembled with the remaining stocks of parts making the half breed. Pure conjecture on my part.

    However if Don Grubee had an engine(38mm which they all were) produced to good standards then dropped out of the market as Grubee did(I don't see them marketing any more) then it makes sense these ex-Grubee engines would show up since manufacturing is already set up. If they all run as good as the one yesterday Im all in for them.
     
  11. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    Just discovered another difference in the GT5. It has nicer machined drive gears that are wider. The cover form most CGs wont fit.
     
  12. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    Where did the engine you speak of here come from?

    Was it an Ebay vendor or another source if you don't mind me asking?

    Many people on here all the time searching for kits they can have more faith in and at least have an idea of what engine geometry they'll be getting since so many vendors don't list what the negine actually is.

    I think most of the vendors dont really know what they have, the Half Breed I got recently was listed as a 40mm stroke engine but as soon as I pulled the jug I saw the ZAE50 Rod and then after sliding the jug back on seen that the piston was down in the hole at TDC about 1/16", this kit came from Honk Kong and from a vendor who sell everything imaginable so I had no doubt it was a crap shoot when I ordered it.

    I know I have heard that mingsinternational sells GT5's, rose326a sells GT5's and another vendor called sashawigs2009 sells GT5 type engines, I'm sure there are others also but these are the ones that have been known for sure to be selling the high pin piston GT5 engines.
     
  13. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    Wow, wish you had got some photos of that to share, I have seen engines where the gears are aligned better but I dint remember seeing one that actually hade wider gears that requires a wider clutch side cover.
     
  14. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    Here ya go. The old style cover wont fit the GT5 but of course the GT5 fits the old motor. We are maybe finally getting some of the latest engineering. Bet they hosed off all the old stuff first. These seem like quality(for CGs) motors.
     

    Attached Files:

    • 007.JPG
      007.JPG
      File size:
      367.8 KB
      Views:
      67
    • 008.JPG
      008.JPG
      File size:
      444.3 KB
      Views:
      63
  15. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    Those do stand out farther dont they...hmmmm

    people who have that engine may not be able to use the chrome and other after market covers.

    did the engine come with the socket head bolts or did you replace the hardware?
     
  16. cannonball2

    cannonball2 Active Member

    Joined:
    Oct 28, 2010
    Messages:
    3,556
    Likes Received:
    22
    Your right on aftermarket covers. The standard cover hits the clutches center leaving a 1/8" gap. I had robbed this engines cover to use on my wet clutch engine. Couldnt figure what the heck was wrong until I checked the other engine and saw the taller cover.

    I retapped the holes in the case to 1/4 20 using a bottoming tap to use the entire bolt hole, the Chinese for some reason only favor the first half. Just cant see using those crappy combo screws to hold the case together. I can torque these.
     
  17. mapbike

    mapbike Active Member

    Joined:
    Mar 14, 2010
    Messages:
    5,380
    Likes Received:
    2
    I guess this engine with wider gear and cover will be something else we have to watch out for now....

    Oh yeah, the holes do tap out nicely with a 1/4x 20 Ive done mounting stud holes with it on one of my engines, works great and gives a larger strong hold or stud.
     
  18. Davezilla

    Davezilla New Member

    Joined:
    Mar 15, 2014
    Messages:
    2,708
    Likes Received:
    3
    I did the same thing on my Dax engine before installing, drilled and tapped it to 1.4 x 20 and bolted it directly to a bracket welded to the frame. I don't like torquing bolts directly into the aluminum so I used longer bolts with a jam nut so the bolts go in just above finger tight then the jam nuts get torqued to 10 ft/lb which prevents thread wear in the aluminum.
    There was enough room to drill and tap for the M8x1.25 hardware but since I already had the 1/4x20 on hand I went with that.
    The case also had the narrow frame spacing on the front side but there was also plenty enough metal for me to use a die grinder and a 1" carbide rotary file to widen it and match the angle to my frame.
     
  19. frank66

    frank66 New Member

    Joined:
    Jan 15, 2015
    Messages:
    207
    Likes Received:
    0
    use 3 gaskets and any cover will fit. but yea my gt5a is like this too.
     
  20. CarpsCustoms

    CarpsCustoms New Member

    Joined:
    Jan 27, 2014
    Messages:
    109
    Likes Received:
    0
    so im trying to understand all of this...the new bottom end i ordered has the FM80 rod, so that means im supposed to end up building a 40mm stroke right???

    How do i know where to order the correct jug & piston?

    I hope the ones i already have are right..
     

Share This Page